Cystic Fibrosis (CF) manifests itself as an abnormality in the function of epithelial membranes (sweat glands, respiratory epithelium, pancreas, perhaps intestine and others). Recent studies suggest a defect in C1 permeability resulting in an impairment of active C1 secretion. Preliminary studies with tracheal cells in primary culture suggest that the defect is in the regulation of a Cl channel, since it can be observed in whole cell patch-clamp studies but not in apical membrane patches removed from the cell. The nature of the regulatory defect is entirely unknown. Another apparent abnormality of CF epithelial cells is their tendency (at least in the respiratory tract) to bind Pseudomonas organisms. This increased adherence appears to be peculiar to Pseudomonas and does not occur with a number of other bacteria. Cells from sweat glands, trachea and nasal polyps of CF patients and suitable controls have been maintained in primary culture for only 2-3 weeks. Existence of a transformed cell line carrying the CF defect will make it far easier to determine the precise nature of this defect and how it affects cell function. We propose in this study to culture CF epithelial cells, along with suitable controls, and to perpetuate these cells by transformation with viral DNA. We will assay cells in primary culture and also transformed cells for C1 conductance and for capacity to bind Pseudomonas pili. C1 conductance will be assayed both by whole cell patch clamp and by uptake of a halide radioisotope.